Experiment 1 Conservation of Momentum In this experiment you will demonstrate transfers of momentum similar to those of the Newton s Cradle system Figure 1 The velocity of a marble after impact depends on the original velocity and the mass of the objects at hand Materials 5 Marbles 2 Rulers Procedure Part 1 1 Use two rulers and make a runway between them by laying them flat on a level surface with the edges of each ruler parallel The runway should be just wide enough for the marbles to pass through 2 Line up four marbles in the center of the runway and ensure they are all touching 3 Take the other marble and place it at one end of the runway Flick it so it collides with the other marbles Observe what happens to the four stationary marbles 4 Try different speeds for flicking the marble into the four stationary marbles and observe how that changes the collision Record the number of marbles that leave the runway in Table 1 5 Repeat Steps 3 and 4 with three stationary marbles in the runway and two flicked marbles 6 Repeat Steps 3 and 4 with two stationary marbles in the runway and three flicked marbles 7 Repeat Steps 3 and 4 with one stationary marble in the runway and four flicked marbles 8 Repeat Steps 3 and 4 with a new combination of stationary marbles I the runway and flicked marbles Table 1 Collision Data Moving and Stationary Marbles Number of Flicked Number of Stationary Number of Marbles that 2014 eScience Labs LLC All Rights Reserved Marbles Marbles Leave the Runway 1 4 0 2 3 1 3 2 1 4 1 3 Part 2 1 Use two rulers and make a runway between them by laying them flat on a level surface with the edges of each ruler parallel The runway should be just wide enough for the marbles to pass through 2 Identify one end of the runway as the left side of the runway and the other the right side of the runway 3 Line up one marble at each of the runway 4 Flick the marbles so they experience a head on elastic collision 5 After the collision record the number of marbles that leave the right and left side of the runway in Table 2 6 Try different speeds for the marbles and observe how that changes the collision 7 Repeat Steps 3 6 for the combinations of marbles in Table 2 Table 2 Collision Data Moving Marbles Number of Marbles Number of Marbles Number of Marbles that Number of Marbles that on Right Side of on Left Side of Leave the Right Side of Leave the Left Side of the Runway Runway the Runway Runway 1 1 0 0 1 2 0 0 1 3 1 0 1 4 1 1 2 2 1 1 2 3 0 1 Post Lab Questions 1 What kind of collision is exhibited by the marbles in this experiment and why 2014 eScience Labs LLC All Rights Reserved Inelastic because some of the energy is wasted into deformation while two marbles stone collide each other 2 When one marble hit the end of the line of marbles how many shot off the other end Describe the momentum of the set of marbles before and after the collision assume elastic collisions One marble initially will have a momentum of mv The final momentum will also have to be mv 3 How did the speed of the marble that comes off the end of the line change as you increased the speed of the marble that travels down the chute Use what you know about the conservation of momentum to describe what is happening P mv mv is constant and speed of marble as it changes according to conservation of momentum So as you increase the speed you increase the momentum and power that the marble shoots off at 4 What happened when you sent two marbles down the runway Is this what you predicted Explain why or why not As predicted they came out with the same momentum 5 How did the result change when both marbles were moving toward each other before the collision They moved together and the same rate and then collided had an energy exchange and came to a hault 6 What do you predict would happen to two marbles after a collision if you slowly rolled a marble down the runway and then flicked a second marble faster in the same direction The second marble would hit the first and there would be a transfer of energy Experiment 2 Egg Drop 2014 eScience Labs LLC All Rights Reserved When a fragile object is subject to a sudden acceleration the strain on the material can cause it to break By increasing the time and distance over which an object accelerates or decelerates you can prevent damage that might occur otherwise even if the total change in momentum is the same In this experiment you will design an apparatus to decelerate a falling egg so that it does not break Materials 6 Washers Masking Tape 1 Plastic Egg Ruler Scissors Large Bowl 5 10 Printer or Notebook Paper Sheets Various Household Items For Egg Apparatus Design You Must Provide Procedure 1 Find an area outside that can be easily cleaned up Note A porch area works well if there is a step you can stand on to drop your egg directly over your apparatus 2 To increase the mass of the egg open the plastic egg place six washers inside and snap the egg back together 3 Tape three sheets of paper over the top of your bowl Construct a hypothesis to predict whether or not the egg will break open if you drop it from a high point onto the paper Include your hypothesis in Post Lab Question 1 4 Drop the egg from shoulder height so that it lands in the large bowl Did the egg break open What happened to the paper Record your observations in Table 3 5 If the egg broke open in Step 3 replace it with six washers and snap the egg back together 6 Space pieces of paper inside the bowl so that there are three layers 2 or 3 cm apart Figure 4 Theoretically the egg will break through each layer in succession before reaching the bottom 2014 eScience Labs LLC All Rights Reserved Figure 4 Step 6 reference 7 If your egg still breaks open add more layers to your apparatus Record the amount of layers you use in Table 3 8 Put the egg back together and drop the egg on the apparatus with new layers 9 Can you design a better apparatus to prevent the egg from breaking Try some other materials you have around your house Table 3 Egg Drop Data Paper Placement Egg Observations 3 Sheets at the Top of the Bowl Broke open 3 Sheets Spaced About 2 to 3 cm Apart Remained shut Post Lab Questions 1 Did you come up with a design that prevents the egg from breaking If yes explain how it worked If not explain why …
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